OF DEAD WHALES, SEEPS AND BENTHIC FORAMINIFERA: COMPARISONS OF THE ECOLOGY OF WHALE FALLS AND METHANE SEEPS ON THE EASTERN PACIFIC MARGIN

The geochemical characteristics typical of large carcasses and methane seepage on the seafloor generate extreme habitats, including those that are conducive to colonization by chemosynthesis-based communities. Comparisons of rose Bengal stained foraminifera in these habitats indicate that foraminiferal assemblage abundances are appreciably lower at whale falls compared with those found in "background" and seep environments. No endemic foraminiferal taxa were found in whale fall or seep assemblages, athough these environments can affect abundances, species patterns, and stable isotopic variability of test carbonate. Calcareous assemblages from both whale fall and seep habitats include Chilostomella, Globobulimina, Uvigerina and Bulimina. Infaunal distribution patterns of these taxa are comparable to those in "background" environments. These findings have important implications for the ecological plasticity and range of tolerances of the foraminiferal taxa that live both within and outside of extreme habitats.